Project Summary Animals, including humans, interact with their chemical environment through specialized receptor cells found within the nasal epithelium. Upon odorant binding, these neurons transmit information to the olfactory bulb, the initial site of olfactory sensory processing. However, at present, our understanding of how these cells ultimately communicate information about odor identity and concentration to the brain in intact animals is limited. I propose that olfactory receptor neurons are a highly diverse population of cells in terms of their odor responses within a sampling event. Furthermore, heterogeneous activity among receptor neurons may be a mechanism to preserve non-redundant information about the sensory environment. Aim 1 will examine how populations of olfactory receptor neurons encode odor mixtures. Aim 2 will test the hypothesis that individual olfactory receptor neurons heterogeneously respond to odors. Together, these aims will provide novel insights into mechanisms of sensory transduction in the mammalian olfactory system.